TY - JOUR AU - ZONG Xian-gang AU - JIANG Ming-xing PY - 2016 TI - Effects of dauricine on slow action potentials in myocardium JF - Acta Pharmacologica Sinica; Vol 11, No 3 (May 1990): Acta Pharmacologica Sinica Y2 - 2016 KW - N2 - The effects of dauricine were examined on the slow action potentials induced by both high K+ (24 mmol/L) or TTX (40 mumol/L) in guinea pig papillary muscles and in sinoatrial node cells of rabbit. Dauricine 40 mumol/L decreased the maximal upstroke velocity (Vmax) of slow action potentials and prolonged the action potential duration at 50% repolarization (APD50). Bay K 8644 (50 nmol/L) increased the amplitude and Vmax of slow action potentials, which were antagonized by dauricine (40 mumol/L). An inhibitory influence of dauricine on the action potential amplitude was observed in papillary muscles superfused with Tyrode's solution containing high K+ and in rabbit sinoatrial node cells, but it was not with TTX. The resting potentials of the 3 slow action potentials were not affected by dauricine. The results suggest that dauricine possesses calcium-antagonistic effect. UR - http://www.chinaphar.com/article/view/5491